We have designed a study to prospectively determine whether there is a difference in outcome between the transfusion of old blood (5-6 weeks) vs. new blood (2-7 days) in a Staphylococcus aureus pneumonia model of sepsis and normal controls. We have completed the initial dose response study determining a survival profile in response to increasing bacterial challenge. A dose of 1.25 x 109 cfu was determined to result in the 50-70% mortality designed in the study. A mortality study comparing the effects of 7 and 42 day old stored blood during critical illness has also been completed. A followup study looking at the role of the amount of blood transfused has also been completed. The first study applying a therapy by washing the stored cells is currently underway. The data associated with the mortality study has been analyzed and is currently being written up. To be followed by the dose response study and the transfused blood volume study.